"Politicians like to talk about the income tax when they talk about overtaxing the rich, but the income tax is just one part of the total tax system. There are sales taxes, Medicare taxes, social security taxes, unemployment taxes, gasoline taxes, excise taxes - and when you add up all of those taxes [many of which are quite regressive], and then you look at how they affect the rich and the poor, you essentially end up with a system in which the best off 20 percent of Americans pay one percentage point more of their income than the worst off 20 percent of Americans."